ClassNK has added Japan’s first hydrogen-fueled tugboat TEN-OH to its register, which is built by TSUNEISHI SHIPBUILDING .

This vessel was developed and build under the “Nippon Foundation Zero Emission Ships Project”, a grant program by The Nippon Foundation aimed at developing ships with zero CO2 emissions.

Based on discussions among the parties involved during the planning stage of the vessel, ClassNK reviewed the safety requirements and countermeasures for hydrogen-fueled ships by applying Part GF of its “Rules and Guidance for the Survey and Construction of Steel Ships” etc.

These reviews focused on issues such as preventing explosions caused by the high ignitability of hydrogen and mitigating the potential impacts of hydrogen fuel leakage on crew members and the environment.

On completion of the necessary surveys in line with the relevant class rules etc., ClassNK added the vessel to its register on 9 October 2025.

Going forward, ClassNK will continuously support the safe operation of the vessel through surveys in service, and not only that, support industry’s effort toward decarbonization through utilizing the knowledge and experience gained from the surveys for keeping its guidelines up to date and contributing to establishment of the appropriate international standard.